Sinister Diesel is your one stop shop for Ford, Chevy, GMC, and Dodge diesel performance parts. Sinister Diesel is also the number one source for Diesel Racing Components, Exhaust Systems, Tuners, Ford Powerstroke, Dodge Cummins, and GM Duramax engine repair parts, upgraded EGR coolers, lighting, bumpers, grilles, and suspension components from our parent company Sinister MFG & Sinister Diesel®. We offer the biggest names in the industry to help you repair or modify your Powerstroke, Cummins, or Duramax diesel engine.
Is Sinister Diesel legit?
Sinister Diesel (sinisterdiesel.com) has a 4.5 out of 5 rating on OK.one, based on 198 user reviews collected here. It is listed under Vehicles & Transportation and its reputation is excellent. 86% of reviews are 4 stars or higher and 6% are 1 star; The business has replied to 44% of negative reviews; Reviews mostly discuss Product, Quality, User experience. Last updated 2026-09-08.
What reviewers say
AI generated
Reviewers overwhelmingly had a great experience with this company. Customers frequently praise the high quality and outstanding performance of the products, noting that everything works exceptionally well and fits their trucks perfectly. People also appreciate the fast shipping times and secure packaging, making the entire purchasing process remarkably smooth and easy.
However, some people mentioned frustrating issues with unexpected backorders and prolonged delivery delays. A few consumers also noted that certain replacement parts required unexpected modifications or extra adjustments during installation. Despite these occasional challenges, most buyers remain very satisfied with their overall purchases and intend to order again.
Auto-generated from all reviews of this business. For reference only.
Thank you for the honest and speedy reply. I expect that from a reputable business and very much appreciate it. I only wish you had an engine cover to fit my motor. Let me know if you decide to fabricate one for my vehicle. You have fine products. I appreciate the sincere call from Katie and adjusted my rating accordingly.
Original Post
I ordered an engine cover for my 1999 7.3L Powerstroke Ford F250 XLT. Got the part in a reasonable amount of time. It looked amazing and very well built. It didn't come close to fitting my motor. Tried calling customer service CS and was prompted to use the contact us link. I received an RMA in an email with instructions. I mailed it back at my expense ($57) requesting an exchange. I sent another note in the same fashion due to no mention of exchange. Katie
from CS called and left a message that this part did not fit early 1999 model years. Their website part description states, in part .."Fits 1999-2003 Powerstroke." I called Katie back and asked for a "return shipping" refund since this was not my mistake. She said no. Great product, poor return policy for legitimate returns.
Reply from Sinister Diesel2024-12-05
Hi Doug, I forwarded this to Customer Service this morning. We appreciate the honest feedback and the opportunity to improve. You are correct, the website does need an update regarding that product, and as I understand, Katie has reached out to make sure you are being fully refunded. We work hard to provide a 5-star experience to each customer, and hope you will give us another chance in the future.
Hi Brian, we are glad to hear that delivery was quick and that you are happy with your products. We work hard to make each experience 5-star. We appreciate your review & your business!
Received a faulty gpcm and sent it back for an exchange.
Reply from Sinister Diesel2024-10-29
Hi Robert! Katie with our customer service department (she's the best!) said she was able to help you out with your order. She said given the opportunity that you would like to change your review. We work hard to provide a 5-star experience and hope we were able to make this right. Here are there instructions to edit your review. We appreciate your business and the chance to earn your business.
Log into their Trustpilot account, navigate to "My Reviews," locate the review they want to edit, click "Edit," make the necessary changes to the text and rating, and then submit the updated review
Top notch product and top notch customer service! I was told originally that my turbo could be a 3-4 week wait but recieved it in about 2 weeks. Beautiful product that performs just as good as it looks!
Reply from Sinister Diesel2024-10-24
Hi Jake - we work hard to provide a 5-star experience to each customer, happy to hear that we hit the mark with you. We appreciate your review & your business!
Parts ordered were packed well i protective packaging and shipped quickly. Received everything in approximately 4 days in very good condition, all parts fit exactly and were very easy to install. Degas tank and coolant bypass filter kit both installed in less than an hour! Very pleased with the materials and workmanship on the parts, they look great. Will be making more upgrades to my 6.0L soon using Sinister Diesel parts!
Reply from Sinister Diesel2024-10-24
Hey Bruce - we love to hear it! Thank you for your review & your business - we appreciate it.
I had a part missing, and it was immediately shipped upon request.
Reply from Sinister Diesel2024-10-24
Hi Jesse - we work hard to remedy any problems that come up as quickly as possible. We appreciate you reaching out and allowing us to correct the situation. Thank you for your review and your business!
Looks great, only a little difficulty installing. Very excited about not having a failure and getting rid of the plastic OEM junk.
Reply from Sinister Diesel2024-10-24
Hi Randy - we are glad to hear that it looks great - reach out in the future if you have any difficulty installing and we'd love to see if we have any helpful tips to make it easier. We appreciate your business!
poor instructions and knowledge of year discrepancy
Instructions for the regulator were poor at best way to vague also the two 6mm bolts for the stc fitting were to long and caused the o-ring to blow out the 04-05 crossover block require shorter bolts had to tear down twice if I was paying shop time the would have costed me over $1200
Reply from Sinister Diesel2024-08-16
Hi JR, One of our customer service reps will be reaching out to you. I am sorry to hear that the instructions were not clear and that there was an issue with the installation. We work hard to provide the best customer experience and products - so we appreciate your feedback as an opportunity to improve. Please respond here or to our CS rep with any tips that would have made the install instructions clearer and easier to follow. Thank you
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